1. Field
The present disclosure relates generally to an improved circuit system and, in particular, to a method and apparatus for limiting the flow of currents in circuits. Still more particularly, the present disclosure relates to a method and apparatus for limiting a current that flows between a source and a load.
2. Background
Spikes in voltage, current, or both may result in damage to electrical circuits in devices. These devices may include, for example, a power supply, a processor unit, a sensor, or other devices.
A spike is a fast, short duration electrical transient that may occur in a voltage or a current in an electrical circuit. The spikes may be caused by short circuits, lightning strikes, electromagnetic pulses, or other sources.
For example, a power supply in a spacecraft may be temporarily short circuited when struck by the energetic particles found in a space environment. A current spike caused by this temporary short circuit may damage the power supply, the device struck by the energetic particle, or other circuits in other devices in the spacecraft.
In another example, a lighting strike may cause a spike in circuits for devices in a building. This spike may also damage circuits in these devices.
Currently, devices may be used to protect against surges. For example, a surge protector is a device that may be used to protect against the surges in voltage or currents. The surge protector may include diodes, fuses, or both diodes and fuses to protect against spikes in a device such as a power supply.
Fuses may be used to protect against the amount of current flowing but do not limit the direction of current flow. Diodes may be placed in series to protect fuses in the device against current flowing in an undesired direction in the power supply.
These diodes, however, consume additional power. Also, the diodes only limit the flow of current in one direction. The additional use of power may be more than desired, especially when a limited amount of power is available from a power source.
Also, in addition to using more power than desired, current devices used to protect against spikes are physically separate devices from those devices being protected. For example, a surge protector device may be connected to a second power supply, a load, or both the second power supply and the load.
In some cases, these surge protector devices may require more space than desired. Within a spacecraft, the amount of space available for devices is very limited as compared to terrestrial applications.
Therefore, it would be desirable to have a method and apparatus that take into account at least some of the issues discussed above, as well as other possible issues. For example, it would be desirable to have a method and apparatus that manage current flow that may flow in directions between two devices in a manner that solves a technical problem with power used, space needed, or both power used and space needed to manage the flow of current between two devices.